Mono-crystalline silicon growth apparatus

ABSTRACT

A mono-crystalline silicon growth apparatus is provided. The mono-crystalline silicon growth apparatus includes a furnace, a support base disposed in the furnace, a crucible disposed on the support base, and a heating module. The support base and the crucible do not rotate relative to the heating module, and an axial direction is defined to be along a central axis of the crucible. The heating module is disposed at an outer periphery of the support base and includes a first heating unit, a second heating unit, and a third heating unit. The first heating unit, the second heating unit, and the third heating unit are respectively disposed at positions with different heights corresponding to the axial direction.

CROSS-REFERENCE TO RELATED PATENT APPLICATION

This application is a divisional application of U.S. patent applicationSer. No. 16/727,941 field on Dec. 27, 2019, which claims the priority ofTaiwan patent application No. 107147827, filed on Dec. 28, 2018, andentitled “MONO-CRYSTALLINE SILICON GROWTH METHOD”, now pending. Theentirety of each of the above-mentioned patent applications is herebyincorporated by reference herein and made as a part of thisspecification.

Some references, which may include patents, patent applications andvarious publications, may be cited and discussed in the description ofthis disclosure. The citation and/or discussion of such references isprovided merely to clarify the description of the present disclosure andis not an admission that any such reference is “prior art” to thedisclosure described herein. All references cited and discussed in thisspecification are incorporated herein by reference in their entiretiesand to the same extent as if each reference was individuallyincorporated by reference.

FIELD OF THE DISCLOSURE

The present disclosure relates to a crystal growth apparatus, and moreparticularly to a mono-crystalline silicon growth apparatus.

BACKGROUND OF THE DISCLOSURE

A conventional silicon growth apparatus is configured to heat to melt asolid raw material and solidify to crystallize the melted raw materialto form a crystal rod. In addition, because the Czochralski Method(i.e., CZ method) is the primary method used in a conventional processto manufacture a crystal rod, conventional mono-crystalline silicongrowth methods are also limited thereto. As a result, development inthis field has been limited, and still has room for improvement.

SUMMARY OF THE DISCLOSURE

In response to the above-referenced technical inadequacies, the presentdisclosure provides a mono-crystalline silicon growth apparatus toimprove on issues associated with obstacles against development in thisfield.

In one aspect, the present disclosure provides a mono-crystallinesilicon growth method including a preparation step, an initiation step,a shoulder-forming step, a body-forming step, and a tail-forming step.The preparation step is implemented by disposing a silicon melt in acrucible of a mono-crystalline silicon growth apparatus, wherein themono-crystalline silicon growth apparatus includes a support basesupporting the crucible and a heating module disposed at an outerperiphery of the support base, and the support base and the crucible donot rotate relative to the heating module. The initiation step isimplemented by solidifying a liquid surface of the silicon melt to forma crystal and horizontally growing the crystal toward a side wall of thecrucible to increase an outer diameter of the crystal. Theshoulder-forming step is implemented by adjusting a thermal field aroundthe crucible when the outer diameter of the crystal reaches at least 90%of a predetermined value so that the outer diameter of the crystalreaches the predetermined value and the crystal is defined as a headcrystal, and vertically growing the head crystal toward an inner bottomsurface of the crucible. The body-forming step is implemented byreducing a total heat output of the heating module so that the headcrystal continuously crystallizes to form a first stage crystal,continuously reducing the total heat output of the heating module sothat the first stage crystal continuously crystallizes to form a secondstage crystal, and reducing the total heat output of the heating moduleagain so that the second stage crystal continuously crystallizes to forma third stage crystal. The tail-forming step is implemented by reducingthe total heat output of the heating module so that the third stagecrystal continuously crystallizes to form a tail crystal, and detachingthe tail crystal from the crucible to form a mono-crystalline siliconingot by solidifying the silicon melt.

In one aspect, the present disclosure provides a mono-crystallinesilicon growth apparatus including a furnace, a support base disposed inthe furnace, a crucible disposed on the support base, and a heatingmodule disposed at an outer periphery of the support base. The supportbase and the crucible do not rotate relative to the heating module, andan axial direction is defined to be along a central axis of thecrucible. The heating module includes a first heating unit, a secondheating unit, and a third heating unit. The first heating unit, thesecond heating unit, and the third heating unit are respectivelydisposed at positions with different heights corresponding to the axialdirection.

Therefore, the mono-crystalline silicon growth method of the presentdisclosure is provided. The mono-crystalline silicon growth apparatusincludes the support base and the crucible which do not rotate relativeto the furnace. The heating module can effectively and appropriatelyadjust a temperature around the crucible to effectively control adirectional solidification of a seed crystal and a crystal growth in acrystal growth process of the mono-crystalline silicon ingot so as toimprove crystal growth effect. As a result, a quality of themono-crystalline silicon ingot is improved. Therefore, by using themono-crystalline silicon growth method, a usage rate of the crystal rodand a production yield are increased.

These and other aspects of the present disclosure will become apparentfrom the following description of the embodiment taken in conjunctionwith the following drawings and their captions, although variations andmodifications therein may be affected without departing from the spiritand scope of the novel concepts of the disclosure.

BRIEF DESCRIPTION OF THE DRAWINGS

The present disclosure will become more fully understood from thefollowing detailed description and accompanying drawings.

FIG. 1 is a sectional view of a mono-crystalline silicon growthapparatus of the present disclosure according to an embodiment of thepresent disclosure.

FIG. 2 is a partial enlarged view of a hard shaft in FIG. 1.

FIG. 3 is a schematic diagram of the mono-crystalline silicon growthapparatus forming a mono-crystalline silicon ingot according to theembodiment of the present disclosure.

FIG. 4 is a flowchart of a mono-crystalline silicon growth method of thepresent disclosure according to the embodiment of the presentdisclosure.

FIG. 5A to FIG. 5F are schematic diagrams of the mono-crystallinesilicon growth method of the present disclosure according to theembodiment of the present disclosure.

DETAILED DESCRIPTION OF THE EXEMPLARY EMBODIMENTS

The present disclosure is more particularly described in the followingexamples that are intended as illustrative only since numerousmodifications and variations therein will be apparent to those skilledin the art. Like numbers in the drawings indicate like componentsthroughout the views. As used in the description herein and throughoutthe claims that follow, unless the context clearly dictates otherwise,the meaning of “a”, “an”, and “the” includes plural reference, and themeaning of “in” includes “in” and “on”. Titles or subtitles can be usedherein for the convenience of a reader, which shall have no influence onthe scope of the present disclosure.

The terms used herein generally have their ordinary meanings in the art.In the case of conflict, the present document, including any definitionsgiven herein, will prevail. The same thing can be expressed in more thanone way. Alternative language and synonyms can be used for any term(s)discussed herein, and no special significance is to be placed uponwhether a term is elaborated or discussed herein. A recital of one ormore synonyms does not exclude the use of other synonyms. The use ofexamples anywhere in this specification including examples of any termsis illustrative only, and in no way limits the scope and meaning of thepresent disclosure or of any exemplified term. Likewise, the presentdisclosure is not limited to various embodiments given herein. Numberingterms such as “first”, “second” or “third” can be used to describevarious components, signals or the like, which are for distinguishingone component/signal from another one only, and are not intended to, norshould be construed to impose any substantive limitations on thecomponents, signals or the like.

Mono-Crystalline Silicon Growth Apparatus

Referring to FIG. 1 to FIG. 3, an embodiment of the present disclosureprovides a mono-crystalline silicon growth apparatus 100 including afurnace 1, a support base 2 disposed in the furnace 1, a crucible 3disposed on the support base 2, a heating module 4 disposed at an outerperiphery of the support base 2, and a heat adjusting module 5 disposedin the furnace 1 and above the crucible 3.

It should be noted that the heat adjusting module 5 in the presentembodiment can cooperate with corresponding components mentioned above,but the connection between the heat adjusting module 5 and thecorresponding components is not limited thereto. That is to say, inother embodiments of the present disclosure, the heat adjusting module 5can be used independently or with other components. In addition, thefurnace 1, the support base 2, the crucible 3, and the heating module 4can further cooperate with a component different from the heat adjustingmodule 5 in the present embodiment.

The furnace 1 includes a furnace wall 11 which is substantially in abarrel shape and a heat preservation layer 14 inside of the furnace 1.The furnace wall 11 surroundingly forms an accommodating space 12within, and the heat preservation layer 14 is in the accommodating space12 so as to maintain a temperature inside the furnace 1 so that thequality of a crystal rod in the furnace 1 in a crystal growth processcan be ensured.

In addition, a top side of the furnace 1 has a valve port 13 in spatialcommunication with the accommodating space 12 so that the accommodatingspace 12 can be in spatial communication with the external environmentthrough the valve port 13. The furnace 1 has a mounting groove 111 whichis annular and at an appropriate height inside of the furnace 1, and themounting groove 111 in the present embodiment is at a top side of theheat preservation layer 14, but the present disclosure is not limitedthereto.

The support base 2 is preferably made of a graphite material, but thepresent embodiment is not limited thereto. The support base 2 isdisposed in the heat preservation layer 14 of the furnace 1, the supportbase 2 includes a carrying portion 21 in a bowl shape and a supportportion 22 in a pillar shape, and a top side of the support portion 22is connected to a bottom side of the carrying portion 21.

The crucible 3 can be made of a quartz material, but the presentembodiment is not limited thereto. The crucible 3 is disposed in theheat preservation layer 14 of the furnace 1, and the crucible 3 isdisposed in the carrying portion 21 of the support base 2. In addition,in the present embodiment, an outer surface of the crucible 3 abutsagainst an inner surface of the carrying portion 21, and a top side ofthe crucible 3 slightly extends out of the carrying portion 21 in thebowl shape, but the present embodiment is not limited thereto. Thecrucible 3 has a crucible opening 31 at the top side of the crucible 3,and the crucible opening 31 faces toward the valve opening 13 to befilled with a melt liquid for being heated. In the present embodiment,the melt liquid is a silicon melt M.

Therefore, because the crucible 3 softens and deforms easily under ahigh temperature, the support base 2 can provide the crucible 3 with asufficient supporting force to prevent the crucible 3 from tilting.Moreover, the support base 2 and the crucible 3 in the presentembodiment are limited to not rotate relative to the furnace 1. That isto say, any support bases or crucibles rotating relative to the furnaceare neither the support base 2 nor the crucible 3 in the presentembodiment.

It should be noted that the furnace 1 is defined to have a central axisP, and the valve opening 13, the supporting base 2, and the crucible 3are all mirror-symmetrical relative to the central axis P.

The heating module 4 is disposed in the heat preservation layer 14 ofthe furnace 1 and is disposed at the outer periphery of the support base2. The heating module 4 includes a first heating unit 41, a secondheating unit 42, and a third heating unit 43. The first heating unit 41,the second heating unit 42, and the third heating unit 43 arerespectively disposed corresponding to the axial direction and atpositions with different heights of the support base 2.

In the present embodiment, the first heating unit 41 surrounds and facestoward an upper half of the crucible 3, the second heating unit 42surrounds and faces toward a lower half of the crucible 3 and isdisposed under the first heating unit 41, the third heating unit 43 isdisposed under the crucible, and a projection area formed byorthogonally projecting the third heating unit 43 onto the crucible 3along the central axis P (or a axial direction of a tube body 511mentioned below) falls on an outer bottom surface 32 of the crucible 3,but the present disclosure is not limited thereto. The upper half of thecrucible 3 in the present embodiment refers to a portion extending fromthe crucible opening 31 downward to 50% of a depth of the crucible 3,and the lower half of the crucible 3 refers to a portion extending fromthe inner bottom surface 33 upward to 50% of the depth of the crucible3, but the present disclosure is not limited thereto.

Moreover, the first heating unit 41, the second heating unit 42, and thethird heating unit 43 can be designed to be an annular heating device ora plurality of heating devices arranged annularly, but the presentdisclosure is not limited thereto.

The heat adjusting device 5 is disposed in the furnace 1 and above thecrucible 3. The heat adjusting device 5 includes a diversion tube 51, aplurality of heat preservation sheets 52 disposed on the diversion tube51, and a hard shaft 53 passing through the diversion tube 51. It shouldbe noted that the in the present embodiment, the hard shaft 53cooperates with the diversion tube 51 and the heat preservation sheets52, but the connection between the hard shaft 53 and the diversion tube51 and the connection between the hard shaft 53 and the heatpreservation sheets 52 is not limited in the present disclosure. That isto say, in other embodiments of the present disclosure, the hard shaft53 can be used independently or with other components.

The diversion tube 51 includes a tube body 511 and a carrying body 512.The carrying body 512 is disposed on the mounting groove 111 of the heatpreservation layer 14 in the furnace 1, and the carrying body 512 isannular and has an inner hole 5121. One end (e.g., a top portion 5111 ofthe tube body 511 in FIG. 1) of the tube body 511 is disposed on thefurnace 1 and extends out of the valve opening 13, and the other end(e.g., a bottom portion 5112 of the tube body 511 in FIG. 1) of the tubebody 511 is connected to a side wall of the inner hole 5121 of thecarrying body 512. Moreover, the carrying body 512 surrounds the tubebody 511, and the tube body 511 and the carrying body 512 are both abovethe crucible 3.

In addition, the tube body 511 of the diversion tube 51 and the carryingbody 512 of the diversion tube 51 cooperatively define a central axis,and the central axis is preferably substantially overlapping with thecentral axis P. That is to say, an axial direction of the tube body 511is parallel to the central axis P. Therefore, a projection area formedby orthogonally projecting the tube body 511 onto the crucible 3 alongthe axial direction of the tube body 511 falls on the inner bottomsurface 33 of the crucible 3. Moreover, the tube body 511 is made of amaterial which does not react with crystal growth gas, which isgenerally stainless steel, but the present disclosure is not limitedthereto.

In the present embodiment, the heat preservation sheets 52 arepreferably in an annular shape and sleeved around the tube body 511.That is to say, the heat preservation sheets 52 are stacked and disposedon the carrying body 512 and sleeved around the tube body 511, but thepresent disclosure does not limit the shapes of the heat preservationsheets 52. Each of the heat preservation sheets 52 has a thermalradiation reflective rate greater than or equal to 70%. Moreover, theheat preservation sheets 52 allow only less than 10% of heat at one sideof the heat preservation sheets 52 to pass through the heat preservationsheets 52 to another side of the heat preservation sheets 52.

More specifically, a number of the heat preservation sheets 52 of theheat adjusting module 5 is seven, but in other embodiments of thepresent disclosure, the number of the heat preservation sheets 52 of theheat adjusting module 5 is greater than or equal to three. The heatpreservation sheets 52 are made of molybdenum, but the presentdisclosure is not limited thereto.

Moreover, the heat preservation sheets 52 have a function of reflectingthermal radiation and can reflect heat into the crucible 3. In addition,the bottom portion 5112 of the tube body 511 is connected to the innerhole 5121 of the carrying body 512, and the heat preservation sheets 52are stacked and disposed on the carrying body 512 so that the carryingbody 512 and the heat preservation sheets 52 are outside of the tubebody 511. The carrying body 512 is disposed on the mounting groove 111so that the tube body 511, the carrying body 512, and the heatpreservation sheets 52 are disposed above the crucible 3, furtherforming an obstruction above the heat preservation layer 14 toeffectively control the heat dissipating through a top side of the heatpreservation layer 14.

The hard shaft 53 is in a strip shape and passes through the tube body511 (as shown in FIG. 1 and FIG. 2), and the hard shaft 53 does notrotate relative to the furnace 1. A water flow channel 531, a gas flowchannel 533, and a clamping portion 532 disposed at a bottom side of thehard shaft 53 are disposed in the hard shaft 53.

Both the water flow channel 531 and the gas flow channel 533 can beinjected with a fluid to take away the heat near the clamping portion532 mentioned below. In the present embodiment, the water flow channel531 can be injected with flowing water and the gas flow channel 533 canbe injected with flowing gas, but the present disclosure is not limitedthereto. In addition, the water flow channel 531 preferably spiralssurroundingly around the gas flow channel 533 to provide the hard shaft53 with a better cooling effect, but the configuration relationshipbetween the water flow channel 531 and the gas glow channel 533 is notlimited thereto in the present disclosure.

The clamping portion 532 is disposed at the bottom side of the hardshaft 53, and at least a part of the clamping portion 532 is disposed inthe crucible 3 to clamp a seed crystal 6. In the present embodiment, theclamping portion 532 is adjacent to the water flow channel 531 and thegas flow channel 533 so that the fluid injected into the water flowchannel 531 and the gas flow channel 533 can take away the heat near theclamping portion 532.

In addition, the hard shaft 53 can move back and forth along the axialdirection of the tube body 511 with a pulling speed preferably less thanor equal to 50 mm/hr. When the hard shaft 53 is moving, the clampingportion 532 thereof is maintained in the crucible 3 and movescorrespondingly. The pulling speed of the hard shaft 53 can be changedaccording to the requirements of the crystal growth, and the presentdisclosure is not limited thereto.

Therefore, the fluid injected into the water flow channel 531 and thegas flow channel 533 can take away the heat near the clamping portion532 so as to prevent the clamping portion 532 from being influenced bythe heat of the silicon melt M in the crucible 3, can control the heatin the crucible 3 effectively, and can stabilize a heat convection inthe crucible 3 to maintain a degree of flatness of solidificationbetween a crystal 7 and the silicon melt M.

It should be noted that the gas flow channel 533 of the hard shaft 53 inthe present embodiment can be omitted. That is to say, in anotherembodiment of the present disclosure, only the water flow channel 531and the clamping portion 532 at the bottom side of the hard shaft 53 aredisposed in the hard shaft 53, and the clamping portion 532 is adjacentto the water flow channel 531 so that the fluid injected into the waterflow channel 531 can take away the heat near the clamping portion 532.

Referring to FIG. 1 to FIG. 3, the mono-crystalline silicon growthapparatus 100 in the present embodiment takes advantages of thestructural design of the heat adjusting module 5 and the configurationrelationship between the heat adjusting module 5 and other components,(e.g., the heat preservation layer 14 of the furnace 1, the crucible 3,and the heating module 4). That is to say, the pulling speed and thequality of forming the crystal 7 can be improved through the addition ofthe hard shaft 53, where the fluid in the water flow channel 531 and/orthe gas flow channel 533 takes away the heat of surface solidificationduring the growth of the crystal 7 and the heat conducting from insideof the silicon melt M to the crystal 7. Therefore, a directionalsolidification and a crystallization process of the seed crystal 6melted near the clamping portion 532 can be effectively controlled sothat the seed crystal 6 can preferably form the crystal 7.

According to the above, the first heating unit 41, the second heatingunit 42, and the third heating unit 43 of the heating module 4 aredisposed at an outer periphery of the crucible 3. Therefore, the heatingmodule 4 can provide appropriate heating in the process of forming amono-crystalline silicon ingot 8 to effectively control the growth speedand the growth quality of the mono-crystalline silicon ingot 8.

Mono-Crystalline Silicon Growth Method

Referring to FIG. 4 to FIG. 5F, the present disclosure further providesa mono-crystalline silicon growth method which can be implementedthrough the mono-crystalline silicon growth apparatus 100, but thepresent disclosure is not limited thereto. The mono-crystalline silicongrowth method in the present disclosure includes a preparation stepS110, an initiation step S120, a shoulder-forming step S130, abody-forming step S140, and a tail-forming step S150.

The preparation step S110 is implemented by providing themono-crystalline silicon growth apparatus 100 mentioned above anddisposing the silicon melt M (as shown in FIG. 5A) in the crucible 3 ofthe mono-crystalline silicon growth apparatus 100. The specificstructure of the mono-crystalline silicon growth apparatus 100 isalready described above and will not be reiterated herein. In addition,in other embodiments of the present disclosure, in the mono-crystallinesilicon growth apparatus 100 used for the mono-crystalline silicongrowth method, the heat adjusting module 5 can be replaced by othercomponents.

That is to say, in the preparation step S110, a stacking charge isplaced in the crucible 3, the crucible 3 is heated to form a meltdown bythe heating module 4 of the furnace 1, and the meltdown forms thesilicon melt M after the heating module 4 appropriately heats thecrucible 3. The silicon melt M can be formed by an established method,and will not be reiterated herein.

The initiation step S120 is implemented by solidifying a liquid surfaceM1 of the silicon melt M to form a crystal 7 and horizontally growingthe crystal 7 toward a side wall of the crucible 3 to increase an outerdiameter of the crystal 7.

That is to say, as shown in FIG. 5A to FIG. 5C, the seed crystal 6 isdisposed near the clamping portion 532 of the hard shaft 53 and contactswith the liquid surface M1 of the silicon melt M. A heat output of theheating module 4 is continuously controlled and enables the liquidsurface M1 of the silicon melt M to solidify to form a solid-liquidinterface M2. The heat near the clamping portion 532 is taken away byappropriately injecting the fluid into the water flow channel 531 and/orthe gas flow channel 533 of the hard shaft 53, and as a result, thecrystal 7 having the same crystal structure as that of the seed crystal6 starts to form on the seed crystal 6 and the solid-liquid interface M2of the silicon melt M. Moreover, a solidification and crystallizationprocess includes a neck growth process and a crown growth process.

In the neck growth process, a thermal stress generated by the contactbetween the seed crystal 6 and the solid-liquid interface M2 of thesilicon melt M causes dislocations. When a crown starts to grow, thedislocations disappear (as shown in FIG. 5B). In addition, in the neckgrowth process, the seed crystal 6 is pulled upward rapidly so that adiameter of the crystal 7 during forming decreases to 4 to 6 mm. Morespecifically, in the neck growth process, the dislocations fullydisappear through a pulling technique alternating between fast and slowspeeds, which is implemented by fast pulling (e.g., with a fast pullingspeed within a range of 120 to 200 mm/hr) to decrease a diameter of theneck and slowly pulling (e.g., with a slow pulling speed within a rangeof 40 to 100 mm/hr) to increase the diameter of the neck. The pullingtechnique alternating between fast and slow speeds is implemented manytimes so that the dislocations fully disappear.

In the crown growth process, a pulling speed and a temperature aredecreased after the neck is formed so that the diameter of the crystal 7is increased gradually to a required size and the crown starts to form(as shown in FIG. 5C). A diameter increasing rate (i.e., an angle of thecrown) is the most important factor in this process. If the temperatureis decreased too fast, the shape of the crown becomes rectangularbecause the diameter increases too fast, resulting in the dislocationsto occur and therefore losing the crystal structure. Moreover, in thecrown growth process, the pulling technique alternating between fast andslow speeds can be used to increase a diameter of the crown with theslow pulling speed (such as within a range of 20 to 40 mm/hr).Meanwhile, because a temperature gradient of a thermal field of thecrucible 3 is small, the heating power of the heating module 4 should bereduced carefully to effectively control the heat gradient of thethermal field.

It should be noted that in the starting process, the heat output of thefirst heating unit 41 is preferably from 80% to 120% of the heat outputof the second heating unit 42, and the heat output of the second heatingunit 42 is preferably from 80% to 120% of the heat output of the thirdheating unit 43.

The shoulder-forming process is implemented by adjusting the thermalfield around the crucible 3 when the outer diameter of the crystal 7reaches at least 90% of a predetermined value so that the outer diameterof the crystal 7 reaches the predetermined value and the crystal 7 isdefined as a head crystal, and vertically growing the head crystaltoward an inner bottom 33 surface of the crucible 3. That is to say, inthe present embodiment, the crystal 7 is pulled upward to form the neckand the crown, after a solidification speed between the solid-liquidinterface M2 of the silicon melt M and the crystal 7 is stabilized, thecrystal will neither be pulled nor grown horizontally, and the headcrystal vertically grows downward only through adjusting the heatingmodule 4 and controlling a cooling speed of the crucible 3.

It should be noted that in the shoulder-forming step S130, the heatoutput of the first heating unit 41 is preferably from 150% to 230% ofthe heat output of the second heating unit 42.

As shown in FIG. 5D to FIG. 5F, the body-forming step S140 isimplemented by reducing a total heat output of the heating module 4 sothat the head crystal continuously crystallizes to form a first stagecrystal, continuously reducing the total heat output of the heatingmodule 4 so that the first stage crystal continuously crystallizes toform a second stage crystal, and reducing the total heat output of theheating module 4 again so that the second stage crystal continuouslycrystallizes to form a third stage crystal.

That is to say, after forming the neck and the crown, a diameter of thehead crystal is maintained at the predetermined value by continuouslyadjusting the pulling speed and the temperature, and a multi-stagedcrystal formed by crystallizing for many times as mentioned above iscalled a crystal body. In a crystal body growth process, because thesolid-liquid interface M2 of the silicon melt M and the heating power ofthe heating module 4 gradually decline, a heat dissipation speed of thecrystal body decreases according to a length of the crystal body.

According to the body-forming step S140 in the present embodiment, thetotal heat output of the heating module 4 when forming the first stagecrystal is from 93% to 97% the total heat output of the heating module 4in the shoulder-forming process. In addition, when forming the firststage crystal, the heat output of the first heating unit 41 is from 170%to 240% of the heat output of the second heating unit 42, and the heatoutput of the second heating unit 42 is from 180% to 220% of the heatoutput of the third heating unit 43.

According to the body-forming step S140 in the present embodiment, thetotal heat output of the heating module 4 when forming the second stagecrystal is from 93% to 97% the total heat output of the heating module 4when forming the first stage crystal. In addition, when forming thesecond stage crystal, the heat output of the first heating unit 41 isfrom 170% to 240% of the heat output of the second heating unit 42, andthe heat output of the second heating unit 42 is from 180% to 220% ofthe heat output of the third heating unit 43.

The total heat output of the heating module 4 when forming the thirdstage crystal is from 93% to 97% of the heat output of the heatingmodule 4 when forming the second stage crystal. In addition, whenforming the third stage crystal, the heat output of the first heatingunit 41 is from 180% to 260% of the heat output of the second heatingunit 42, and the heat output of the second heating unit 42 is from 180%to 220% of the heat output of the third heating unit 43.

According to the body-forming step S140 in the present embodiment, theheat output of the first heating unit 41 is higher than the heat outputof the second heating unit 42, and the heat output of the second heatingunit 42 is higher than the heat output of the third heating unit 43.Moreover, each of a volume of the first stage crystal, a volume of thesecond stage crystal, and a volume of the third stage crystal is from23% to 32% of a volume of the mono-crystalline silicon ingot 8.

It should be noted that in the body-forming step S140 of the presentembodiment, the mono-crystalline silicon growth apparatus 100 preferablyreceives the heat through injecting the fluid into the hard shaft 53 sothat the crystal 7 grows in the crucible 3.

The tail-forming step S150 is implemented by reducing the total heatoutput of the heating module 4 so that the third stage crystalcontinuously crystallizes to form a tail crystal, and detaching the tailcrystal from the crucible 3 to form a mono-crystalline silicon ingot 8(as shown in FIG. 3) by solidifying the silicon melt M. An outerdiameter of the mono-crystalline silicon ingot 8 is substantially 90% ofan inner diameter of the crucible 3.

According to the tail-forming step S150 in the present embodiment, a sumof a volume of the head crystal and a volume of the tail crystal is lessthan or equal to 30% of the volume of the mono-crystalline silicon ingot8.

According to the tail-forming step S150 in the present embodiment, thetotal heat output of the heating module 4 when forming the tail crystalis from 93% to 97% of the total heat output of the heating module 4 whenforming the third stage crystal. In addition, when forming the tailcrystal, the heat output of the first heating unit 41 is from 80% to120% of the heat output of the second heating unit 42, and the heatoutput of the second heating unit 42 is from 180% to 220% of the heatoutput of the third heating unit 43.

According to the tail-forming step S150 in the present embodiment, afterdetaching the tail crystal from the crucible 3 in a crystal solidifyingprocess, an inner stress of the crystal 7 is reduced as a result ofcontinuously preserving heat, and the mono-crystalline silicon crystalingot 8 is therefore formed by solidifying the silicon melt M. Themono-crystalline silicon crystal ingot 8 is then slowly cooled down andtaken out of the furnace 1 so that the mono-crystalline silicon crystalingot 8 has better growth.

It should be noted that, when implementing the mono-crystalline silicongrowth method to form the crystal 7, the liquid surface M1 (or aninterface between the crystal 7 and the silicon melt M) of the siliconmelt M is concave because the temperature gradient is small such that astress when the crystal 7 grows is small, and the quality of the crystal7 is further increased.

Therefore, referring to FIG. 1 to FIG. 5F, the mono-crystalline silicongrowth apparatus 100 can be used to implement the mono-crystallinesilicon growth method shown in FIG. 4 to FIG. 5F. In the initiation stepS120 of the mono-crystalline silicon growth method, when the seedcrystal 6 contacts the liquid surface M1 of the silicon melt M tosolidify to form the crystal 7, the fluid in the water flow channel 531and/or the gas flow channel 533 can take away the heat near the clampingportion 532 to prevent the clamping portion 532 from being affected bythe heat of the silicon melt M in the crucible 3. The hard shaft 53 canmove forth and back in the pulling speed along the axial direction ofthe tube body 511. The seed crystal 6 at the clamping portion 532correspondingly moves forth and back in the pulling speed in thecrucible 3 so as to effectively control a seeding operation and aseeding effect of the seed crystal 6 at the clamping portion 532.

According to the present embodiment, the temperature of the thermalfield around the crucible 3 can be adjusted according to growthrequirements of the crystal 7 in the crystallization process. Becausethe fluid in the water flow channel 531 and/or the gas flow channel 533can take away the heat and the heating power (or the total heat output)of the heating module 4, an outer wall and the outer bottom surface 32of the crucible 3 can be appropriately cooled down so that a bottom sideof the crystal 7 is maintained in a solid state and the temperature ofthe crystal 7 in a central region is not affected, which prevents theheat generated by the heating module 4 disposed at an outer periphery ofthe crucible 3 from over-concentrating at four corners and prevents thecrystal 7 growing vertically from sticking to the inner bottom surface33 of the crucible. Therefore, the crystal 7 can be prevented frominternally forming an excessive temperature gradient, the inner stressof the crystal 7 can be effectively controlled so that the growing speedand quality of the crystal 7 growing vertically can be controlledeffectively to provide the mono-crystalline silicon ingot 8 with abetter growth.

In addition, in the crystallization process, with the co-influence ofthe heat adjusting function of the fluid in the water flow channel 531and/or the gas flow channel 533 and the heat preservation function ofthe heat preservation sheets 52, a horizontal temperature gradient ofthe silicon melt M in the crucible 3 is small so as to control thehorizontal crystallization speed of the crystal 7 to be smaller than thevertical crystallization speed of the crystal 7 and prevent the clampingportion 532 from being partially subcooled.

In conclusion, the mono-crystalline silicon growth method in the presentembodiment of the present disclosure uses the support base and thecrucible unrotatably disposed in the furnace, takes advantage of theheating module to appropriately adjust the temperature around thecrucible, prevents the seed crystal from melting unevenly in thecrystallization process of the mono-crystalline silicon ingot, andprevents the crystal from internally forming a temperature gradient thatis too large so that the crystal does not stick to the inner bottomsurface of the crucible, and the inner stress of the crystal cantherefore be controlled. Therefore, the seed crystal goes through thecrystal growing process smoothly, and a crystal growing effect of thecrystal and the quality of the mono-crystalline silicon ingot areimproved. As a result, by using the mono-crystalline silicon growthmethod, a usage rate of the crystal rod and a production yield areincreased.

The foregoing description of the exemplary embodiments of the disclosurehas been presented only for the purposes of illustration and descriptionand is not intended to be exhaustive or to limit the disclosure to theprecise forms disclosed. Many modifications and variations are possiblein light of the above teaching.

The embodiments were chosen and described in order to explain theprinciples of the disclosure and their practical application so as toenable others skilled in the art to utilize the disclosure and variousembodiments and with various modifications as are suited to theparticular use contemplated. Alternative embodiments will becomeapparent to those skilled in the art to which the present disclosurepertains without departing from its spirit and scope.

What is claimed is:
 1. A mono-crystalline silicon growth apparatus,comprising: a furnace; a support base disposed in the furnace; acrucible disposed on the support base, wherein the support base and thecrucible do not rotate relative to the heating module, and an axialdirection is defined to be along a central axis of the crucible; and aheating module disposed at an outer periphery of the support base andincluding a first heating unit, a second heating unit, and a thirdheating unit, wherein the first heating unit, the second heating unit,and the third heating unit are respectively disposed at positions withdifferent heights corresponding to the axial direction.
 2. Themono-crystalline silicon growth apparatus according to claim 1, whereinthe first heating unit surrounds and faces toward an upper half of thecrucible, the second heating unit surrounds and faces toward a lowerhalf of the crucible, the third heating unit is disposed under thecrucible, and a projection area formed by orthogonally projecting thethird heating unit onto the crucible along the axial direction falls onan outer bottom surface of the crucible.